Starting device for discharge lamps

Abstract

A starting device for discharge lamps including an ignitor and a ferromagnetic ballast, composed of a toroidal core, equipped with at least an air gap, and an electric coil wound around the toroidal core.

Claims

1. A starting device for discharge lamps, comprising at least an ignitor and a ferromagnetic ballast, wherein the ferromagnetic ballast is composed of at least a toroidal core, equipped with at least an air gap, and one electric coil, wound around the toroidal core.

2. The starting device according to claim 1, wherein it comprises a capacitor, designed for power factor correction of the current drawn by the lamp and by the ferromagnetic ballast.

3. The starting device according to claim 1, wherein the toroidal core is composed of at least a small plate wound in a spiral over itself, made of ferromagnetic material.

4. The starting device according to claim 1, wherein the toroidal core is composed of small plates in a pack, made of ferromagnetic material.

5. The starting device according to claim 1, wherein the toroidal core is made of solid ferromagnetic material.

6. The starting device according to claim 1, wherein the electric coil made of copper.

7. The starting device according to claim 1, wherein the electric coil is made of aluminium.

8. The starting device according to claim 1, wherein the electric coil is associated with the toroidal core by means of a resin layer.

9. The starting device according to claim 1, wherein it comprises at least an intermediate electrical connection, able to reduce the inductance of the electric coil comprised in the ferromagnetic ballast.

10. A method for making a starting device, comprising at least an ignitor and a ferromagnetic ballast, composed of at least a toroidal core, equipped with at least an air gap, and an electric coil wound around the toroidal core, wherein it comprises at least a step of annealing the toroidal core after the air gap has been created.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further advantages and features of the invention are more apparent in the detailed description which follows, with reference to the accompanying drawings, which illustrate an example embodiment of it without limiting the scope of the invention, in which:

(2) FIG. 1 is a block diagram of the invention;

(3) FIG. 2 is a top view of a component of the invention, with some parts cut away to better illustrate others;

(4) FIGS. 3 and 4 are radial cross-sections of two possible alternative embodiments of the same component as in FIG. 2;

(5) FIG. 5 is a schematic illustration of an alternative embodiment of the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

(6) A starting device for discharge lamps comprises at least an ignitor 1 and a ferromagnetic ballast 3. The ferromagnetic ballast 3 is composed of at least a toroidal core 5, equipped with at least an air gap 5a, and an electric coil 4, wound around the toroidal core 5. That shape of the ferromagnetic ballast 3 allows the obtainment of lasting high energy efficiency, resulting in corresponding improved efficiency of the device 10 and the lamp 20 with which it is associated.

(7) In a preferred embodiment of the invention, schematically illustrated in FIG. 1, the starting device 10 comprises a power factor correction capacitor 2 for the current drawn by the lamp 20 and by the ferromagnetic ballast 5.

(8) The toroidal core 5 may be made in various ways: it may be composed of one or more small plates made of ferromagnetic material wound over themselves in a spiral, as shown in FIG. 4, of small plates of ferromagnetic material in a pack, as shown in FIGS. 2 and 3, or even solid ferromagnetic material. Annealing of the ferromagnetic material after the air gap 5a has been created in any case guarantees improvement of the magnetic properties of the core, reducing losses caused by magnetic hysteresis.

(9) The electric coil 4 is made of copper. In a possible alternative embodiment, the electric coil 4 is made of aluminium or another conducting material, so as to make the ferromagnetic ballast 3 as a whole less heavy.

(10) The electric coil 4, as illustrated in FIGS. 2, 3 and 4, may be coupled to the toroidal core 5 by means of a resin layer 4a which gives the set of parts greater compactness, guaranteeing that the ferromagnetic ballast 3 will be less noisy due to vibrations, better insulated and more able to withstand corrosion due to weather.

(11) The device 10 may also involve the use of at least one intermediate electrical connection 6, which allows the device 10 to operate using inductance values of the electric coil 4 of the ferromagnetic ballast 3 which are lower than the nominal value, as is schematically illustrated in FIG. 5. This figure shows how the intermediate electrical connection 6 allows the ferromagnetic ballast 3 to be used for ballasts having an input voltage V different to the input voltage V of 220 Volts found in most cases. The intermediate electrical connection 6 also allows different output voltages to be obtained, so as to regulate the luminous flux depending on the energy saving.